6-(2-Aminopropyl)benzofuran or 6-APB and “Benzofury” is a novel entactogen substance of the benzofuran class. It is structurally related to entactogens like MDA, MDMA, 5-APB, and 5-MAPB.
6-APB was first synthesized in 1993 by David E. Nichols as a potential non-neurotoxic alternative to MDMA. However, it did not come into popular recreational use until over a decade later. Thus, it briefly entered the rave scene and global research chemicals market. It was sold along with other novel benzofuran entactogens under the name “Benzofury” before its sale and import were subsequently banned.
Subjective effects include anxiety suppression, disinhibition, muscle relaxation, and euphoria. 6-APB’s effects are commonly compared to those of MDA and other entactogens.
Very little data exists about the pharmacological properties, metabolism, and toxicity of 6-APB. However, it has a brief history of human usage. It has been marketed alongside research chemical entactogens like 5-MAPB and 5-APB as a legal, grey-market alternative to MDMA. Also, it is typically commercially distributed by online research chemical vendors. It is highly advised to use harm reduction practices if using this substance.
6-APB, also known as 6-(2-aminopropyl)benzofuran, is a synthetic molecule of the benzofuran class. The benzofuran class of substances are members of the amphetamine and phenylethylamine classes. Molecules of this class contain a phenethylamine core bound to an amino (NH2) group. This is linked to an ethyl chain with an additional methyl substitution at Rα. 6-APB does not contain a methyl substitution on RN. It is composed of an oxygen-substituted benzofuran ring fused at R3 and R4 of the phenyl ring.
Notably, 6-APB shares this benzofuran ring with related compounds such as 5-APB, 5-MAPB, and 6-MAPB.
Three distinct batches have been in circulation since its initial release to markets. Originally, only hydrochloride was available. Its dosage range shared characteristics most similar to that of MDA in terms of dose-response. However, succinate and fumarate batches both entered the market, and have very different effects by weight. Also, vastly different loose bulk densities.
6-APB is a serotonin–norepinephrine–dopamine reuptake inhibitor (SNDRI). It has Ki values of 117, 150, and 2698 nM for the norepinephrine transporter (NET), dopamine transporter (DAT), and serotonin transporter (SERT), respectively. 6-APB also possesses additional activity as a releasing agent of these monoamine neurotransmitters.
6-APB is a potent full agonist of the serotonin 5-HT2B receptor (Ki = 3.7 nM).It has higher affinity for this target than any other site.
The monoamine neurotransmitters known as serotonin, dopamine and noradrenaline are the global neurotransmitters that modulate the brain’s ability to feel pleasure, motivation, reward, planning, attention, and focus. The result is neuronal activation at a multitude of brain regions which has the net result of producing a combination of stimulating, relaxing, disinhibiting and euphoric effects.